There are only a couple of reasons a 5 flash occurs.
1-the motor is overheated. If you run it a lot in a 15 min period it will do this. To solve this unplug the unit for 15 min and try again.
2-The rpm sensor is bad in the unit, or needs to be reset. This is the sensor that keeps track of the revolutions. It is located in side the motor assembly. This needs to be replaced if the unit moves 6-8" and stops. To rest unplug for 15 min. and then try again, if it still occurs it needs to be replaced.
3-The only other reason for this code is that the trolley is stuck on the top stop bolton the track. It will humm but not move. You will need to take the top bolt out and adjust the up travel down so the door does not operate as far up. thanks BB